Search rolls on after evidence of birth found at river

Police are scouring an area near Cooks River in Earlwood, Sydney, for signs of a newborn baby. (Dean Lewins/AAP PHOTOS)

WHAT IS KNOWN SO FAR

* A man who was walking his dog along Cooks River, at Earlwood in Sydney's southwest, found a placenta and umbilical cord next to the river about 4.30pm on Monday

* Police tested the material and confirmed they belonged to a human

* A large-scale search kicked off on Monday night and continued on Tuesday morning, with forensic teams, divers and a blood detection dog all on-site

* Authorities don't know who the woman is, if she gave birth at the river or went there afterwards, or when the birth take place

* Further forensic testing will be done on the placenta and cord on Tuesday in an attempt to find out who they belong to and the circumstances of the birth

* The mother is being urged to seek medical assistance or attend a local hospital, with police saying her health remains their priority

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